The proposed research will combine beneficiary-specific and grouped data from the claims and eligibility files of Pennsylvania Blue Shield (PBS) for 1975-1979 with individual and household survey information from a sample of PBS subscribers in order to estimate the effects of various features of insurance plan design on the utilization and cost of dental services. Objectives are: (1) to estimate the determinants of dental care demand for distinct socio-demographic population groups and, insurance plan design on utilization and cost; (2) to test for adverse selection among PBS subscribers and to measure its impact on utilization and cost. The claims experience of the universe of PBS subscribers will be used to compare utilization and claims cost among subgroups of PBS eligibles. Household survey data from a sample of approximately 17,400 subscribers in 1979 will be added to claims/eligibility data for these subscribers in order to estimate individual specific demand functions for dental services and to test for adverse selection effects.